Link aggregation technology is also called link convergence, link bundling, or trunking. The link aggregation technology means aggregation of a plurality of independent physical links into one logic link. After the link aggregation, for upper layer MAC clients, the physical links seem to be only one logic link. The link aggregation can increase the bandwidth between network elements, and enhance the reliability and flexibility of connection between the network elements.
Currently, the link aggregation is implemented as follows.
Systems at the two ends of a link exchange link aggregation configuration information by exchanging Link Aggregation Control Protocol Data Unit (LACPDU) packets. Generally, an LACPDU packet has a destination MAC address of 01-80-c2-00-00-02, and has a source MAC address which is an MAC address of a port for sending the LACPDU packet. The LACPDU packet carries identifier information and status information. The identifier information is used to identify units participating in link aggregation. An LACP entity assigns an identifier for each unit participating in link aggregation. Here, the “units” include systems, aggregators, ports, aggregation capability of ports, and link aggregation groups (LAGs) which are participating in link aggregation. Except the aggregation capability of ports that adopts management key values and operation key values as identifiers, identifiers of other units are basically MAC address-based. For the units in the same layer, the identifier information should be unique and be managed globally.
After receiving the LACPDU packet, the LACP entities at the two end systems of the link determine the ports which are allowed to aggregate together according to the “identifiers of aggregation capability of ports” carried in the LACPDU packet, and create or maintain a corresponding LAG. For example, if the LACP entities determine that the “identifiers of aggregation capability of ports” carried in the LACPDU packet are the same as those of an existing LAG, the LACP entities add the link corresponding to the ports to the existing LAG. Furthermore, for example, if the LACP entities determine that the “identifiers of aggregation capability of ports” carried in the LACPDU packet are different from those of all existing LAGs, the LACP entities create a new LAG. After the new LAG has been created, the LACP entities at the two ends of the link need to reach an agreement on the new LAG, and then perform MAC frame transmission by using the newly created LAG.
At present, the MAC frame transmission based on link aggregation is as follows.
A frame distributor distributes MAC frames to the corresponding links in the LAG according to destination addresses (DAs), source addresses (SAs), MAC service data units (M_SDUs), and service classes (service_class) of the MAC frames, so as to perform MAC frame transmission.
During the implementation of the present invention, the inventors find that, the current link aggregation process fails to consider the Virtual Local Area Network (VLAN), and furthermore, the frame distributor also fails to consider the VLAN during the distribution of MAC frames. As a result, the MAC frames cannot be distributed according to VLAN identifiers. If the ports of physical links in the LAG have been classified on the basis of the VLAN, and the VLANs of the ports of the different physical links in the LAG are different, the MAC frames having VLAN identifiers may be distributed to other VLAN links. In order to solve the problem that the MAC frames having VLAN identifiers may be distributed to other VLAN links, it is necessary to ensure that the VLANs of the ports of each link participating in the aggregation have the same configuration during the link aggregation, which, however, influences flexibility of the networking application, increases difficulty of the network design and network maintenance and management, and even causes a case where the link aggregation may only be implemented in a manual manner.